4) In regression models, we usually want to see what happens to the outcome variable when an independent variable of interest that we call 'x' is increased by 1 unit. This is the equivalent of taking the first derivative of the outcome with respect to x. What is for the following values of F(x)? a) F(x) = 5x. b) F(x)= A+Bx c) F(x) = Ln(x), where Ln' denotes natural log. 5) a) What is the first derivative of the following function F(x)? What value does the first derivative below take when x=5? What value does it take when x=9? What value does it take when x=12? For what value of x does the following function take its maximum value? Please clearly show your steps. F(x)= 20x - 1.25x